Wulf Moon has been my short story writing mentor for the past 2 years. I was trained personally by him in the KYD exercise and I am one of those who has told him I attribute a huge part of my first professional short story sale (the story I sold to DreamForge Anvil this year, which will be published in October!) to these exercises.
I still do at least one "Kill Your Darlings" exercise a month as part of his online "Wulf Pack," and even though it is my 2nd year in his Super Secrets workshop, my writing continues to grow from practicing these KYD techniques. It hasn't only changed my writing, it has changed how my brain THINKS about my writing, which has been a monumental shift.
If you're a serious fiction writer looking to take your stories to the next level, I *highly* recommend this workshop. It will teach you techniques you can apply to EVERY story you write to make them more powerful, and will also show you how to create a supercharged, potent story idea from the BEGINNING, so that you're starting with a more powerful story concept from the get-go.
Also, Moon is super friendly and great at explaining things in a way that makes you go "Ohhhhhhh!" I've attended multiple of his virtual classes (in addition to the primary workshop group I'm in with him) and even the Q&A at the ends of his workshops are usually stellar.
This class is being held via Zoom, so you can attend from ANYWHERE (even internationally!).
Full info about the workshop--including his own explanation of how this technique he created helped him win first place in a writing contest from over 30,000 entries!--is at Moon's Facebook post here.